MEMSCON Delivers Building Integrity Monitoring Results

The EU-funded MEMSCON project has delivered its final results on developing a wireless structural integrity monitoring system that can be integrated into the skeleton of a building. The project, which has now officially closed, presented a second-generation system based on MEMS sensors and RFID tags at its final event in Athens, Greece. Holst Centre was involved by developing the ultra-low power readout circuitry.

Evaluating the structural integrity of buildings is an important public safety issue, especially as buildings age or after earthquakes. Until now, such evaluations have relied on visual inspections, which can’t assess hidden damage without destructive testing. As a result, upcoming European Union regulations will make it mandatory to include structural integrity monitoring systems in all new buildings in earthquake zones.

Existing systems use external sensors that are bulky, easily damaged and, if wireless, require large, expensive batteries which must be replaced frequently. Consequently, the MEMSCON project was launched three and half years ago to carry out research into and develop intellectual property (IP) for monitoring solutions that can be placed within a building’s reinforced concrete beams by laborers during construction. These solutions combine MEMS-based accelerometers and strain sensors with RFID tags into one small package.

“This was a very ambitious project that pushed the technology to extremes. The specifications defined by civil engineers were extremely tough. We needed to develop accelerometers that could withstand accelerations up to 2.5g – a peak ground acceleration of 0.5g could be enough to bring down a building. The strain sensors had to handle strains 10 times greater than the yielding strain of the steel rebars they will be attached to. And the system lifetime requirements meant we had to design new ultra-low-power readout electronics,” explained Juan Santana of Holst Centre.

A first-generation proof-of-concept system was installed in a residential building in Athens in 2011. Since then, and drawing on data from the Athens pilot system, the consortium has improved both the hardware and the software. At it’s final meeting in Athens, the consortium presented its results along with the system IP and documentation to the EU and the global civil engineering community.

Besides commercial and residential buildings, the system could be used in structures such as bridges. It can be integrated during construction, or retrofitted to historic buildings such as churches during renovations. Other applications could include car braking systems and structural integrity monitoring in planes. The system’s small size has even led to interest in the dental community, where it could be used to provide quantitative strain information for fitting orthodontic braces, retainers and plates.